An international group of scientists, including researchers at the Medical Research Council (MRC), has discovered 30 genes that control the age at which girls reach sexual maturity. They found that many of the genes responsible for puberty also play a strong role in how the body metabolises fat, establishing new biological links between going through puberty at a young age and being at increased risk of obesity.

This knowledge will help to explain why girls in some families are more likely to go through puberty at an early age, and may eventually help to prevent chronic health problems associated with excessive weight gain.

Reaching puberty at an early age not only puts women at an increased risk of obesity, but is also associated with a number of illnesses and poorer health in later life. A study of more than 100,000 women from Europe, the US and Australia found that many of the genes identified play an important role in the regulation of body weight. The study also identified specific genes involved in hormone regulation and cell development, showing that timing of puberty is controlled by a complex range of biological processes.

Lead author Cathy Elks at the MRC Epidemiology Unit in Cambridge says:

It is interesting that several of the new genes for puberty timing have been linked in other studies to body weight gain and obesity. This suggests that females in some families may inherit a joint genetic susceptibility to weight gain and early puberty.

We know that girls who are overweight are more likely to go through puberty at younger ages. Our findings tell us that being overweight and early puberty are intricately linked. It is also important to understand that these 'common genetic factors' can be modified by changes in lifestyle. If rates of childhood obesity continue to rise we will see many more girls reach puberty at young ages. Conversely, efforts to prevent or reduce childhood obesity will help avoid early puberty.

Senior author Dr Anna Murray at the University of Exeter says:

Scientists have long been fascinated by how the body knows whether it has enough nutrient stores to launch into puberty which leads to reproductive maturation. We found that the timing of puberty is related to fatty acid metabolic pathways. There is evidence that the brain can sense these types of body fats.

The study was supported in the UK by the Medical Research Council and the Wellcome Trust.